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3bd94003 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
1da177e4 LT |
2 | /* |
3 | * Copyright (C) 2003 Sistina Software | |
416cd17b HM |
4 | * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
5 | * | |
6 | * Device-Mapper dirty region log. | |
1da177e4 LT |
7 | * |
8 | * This file is released under the LGPL. | |
9 | */ | |
10 | ||
416cd17b HM |
11 | #ifndef _LINUX_DM_DIRTY_LOG |
12 | #define _LINUX_DM_DIRTY_LOG | |
13 | ||
14 | #ifdef __KERNEL__ | |
1da177e4 | 15 | |
416cd17b HM |
16 | #include <linux/types.h> |
17 | #include <linux/device-mapper.h> | |
1da177e4 LT |
18 | |
19 | typedef sector_t region_t; | |
20 | ||
416cd17b | 21 | struct dm_dirty_log_type; |
1da177e4 | 22 | |
416cd17b HM |
23 | struct dm_dirty_log { |
24 | struct dm_dirty_log_type *type; | |
87a8f240 | 25 | int (*flush_callback_fn)(struct dm_target *ti); |
1da177e4 LT |
26 | void *context; |
27 | }; | |
28 | ||
416cd17b | 29 | struct dm_dirty_log_type { |
1da177e4 LT |
30 | const char *name; |
31 | struct module *module; | |
1da177e4 | 32 | |
ec44ab9d MS |
33 | /* For internal device-mapper use */ |
34 | struct list_head list; | |
35 | ||
416cd17b | 36 | int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti, |
86a3238c | 37 | unsigned int argc, char **argv); |
416cd17b | 38 | void (*dtr)(struct dm_dirty_log *log); |
1da177e4 LT |
39 | |
40 | /* | |
41 | * There are times when we don't want the log to touch | |
42 | * the disk. | |
43 | */ | |
416cd17b HM |
44 | int (*presuspend)(struct dm_dirty_log *log); |
45 | int (*postsuspend)(struct dm_dirty_log *log); | |
46 | int (*resume)(struct dm_dirty_log *log); | |
1da177e4 LT |
47 | |
48 | /* | |
49 | * Retrieves the smallest size of region that the log can | |
50 | * deal with. | |
51 | */ | |
416cd17b | 52 | uint32_t (*get_region_size)(struct dm_dirty_log *log); |
1da177e4 | 53 | |
416cd17b | 54 | /* |
1da177e4 LT |
55 | * A predicate to say whether a region is clean or not. |
56 | * May block. | |
57 | */ | |
416cd17b | 58 | int (*is_clean)(struct dm_dirty_log *log, region_t region); |
1da177e4 LT |
59 | |
60 | /* | |
61 | * Returns: 0, 1, -EWOULDBLOCK, < 0 | |
62 | * | |
63 | * A predicate function to check the area given by | |
64 | * [sector, sector + len) is in sync. | |
65 | * | |
66 | * If -EWOULDBLOCK is returned the state of the region is | |
67 | * unknown, typically this will result in a read being | |
68 | * passed to a daemon to deal with, since a daemon is | |
69 | * allowed to block. | |
70 | */ | |
416cd17b HM |
71 | int (*in_sync)(struct dm_dirty_log *log, region_t region, |
72 | int can_block); | |
1da177e4 LT |
73 | |
74 | /* | |
75 | * Flush the current log state (eg, to disk). This | |
76 | * function may block. | |
77 | */ | |
416cd17b | 78 | int (*flush)(struct dm_dirty_log *log); |
1da177e4 LT |
79 | |
80 | /* | |
81 | * Mark an area as clean or dirty. These functions may | |
82 | * block, though for performance reasons blocking should | |
83 | * be extremely rare (eg, allocating another chunk of | |
84 | * memory for some reason). | |
85 | */ | |
416cd17b HM |
86 | void (*mark_region)(struct dm_dirty_log *log, region_t region); |
87 | void (*clear_region)(struct dm_dirty_log *log, region_t region); | |
1da177e4 LT |
88 | |
89 | /* | |
90 | * Returns: <0 (error), 0 (no region), 1 (region) | |
91 | * | |
92 | * The mirrord will need perform recovery on regions of | |
93 | * the mirror that are in the NOSYNC state. This | |
94 | * function asks the log to tell the caller about the | |
95 | * next region that this machine should recover. | |
96 | * | |
97 | * Do not confuse this function with 'in_sync()', one | |
98 | * tells you if an area is synchronised, the other | |
99 | * assigns recovery work. | |
a4a82ce3 | 100 | */ |
416cd17b | 101 | int (*get_resync_work)(struct dm_dirty_log *log, region_t *region); |
1da177e4 LT |
102 | |
103 | /* | |
f3ee6b2f JB |
104 | * This notifies the log that the resync status of a region |
105 | * has changed. It also clears the region from the recovering | |
106 | * list (if present). | |
1da177e4 | 107 | */ |
416cd17b | 108 | void (*set_region_sync)(struct dm_dirty_log *log, |
f3ee6b2f | 109 | region_t region, int in_sync); |
1da177e4 | 110 | |
416cd17b | 111 | /* |
1da177e4 | 112 | * Returns the number of regions that are in sync. |
416cd17b HM |
113 | */ |
114 | region_t (*get_sync_count)(struct dm_dirty_log *log); | |
1da177e4 LT |
115 | |
116 | /* | |
117 | * Support function for mirror status requests. | |
118 | */ | |
416cd17b | 119 | int (*status)(struct dm_dirty_log *log, status_type_t status_type, |
86a3238c | 120 | char *result, unsigned int maxlen); |
7513c2a7 JB |
121 | |
122 | /* | |
123 | * is_remote_recovering is necessary for cluster mirroring. It provides | |
124 | * a way to detect recovery on another node, so we aren't writing | |
125 | * concurrently. This function is likely to block (when a cluster log | |
126 | * is used). | |
127 | * | |
128 | * Returns: 0, 1 | |
129 | */ | |
130 | int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region); | |
1da177e4 LT |
131 | }; |
132 | ||
416cd17b HM |
133 | int dm_dirty_log_type_register(struct dm_dirty_log_type *type); |
134 | int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type); | |
1da177e4 LT |
135 | |
136 | /* | |
137 | * Make sure you use these two functions, rather than calling | |
138 | * type->constructor/destructor() directly. | |
139 | */ | |
416cd17b | 140 | struct dm_dirty_log *dm_dirty_log_create(const char *type_name, |
87a8f240 MP |
141 | struct dm_target *ti, |
142 | int (*flush_callback_fn)(struct dm_target *ti), | |
86a3238c | 143 | unsigned int argc, char **argv); |
416cd17b | 144 | void dm_dirty_log_destroy(struct dm_dirty_log *log); |
1da177e4 | 145 | |
416cd17b HM |
146 | #endif /* __KERNEL__ */ |
147 | #endif /* _LINUX_DM_DIRTY_LOG_H */ |